Apparatus for transporting viscous oils



March 3, 1959 s. D. LAWSON APPARATUS FOR TRANSPORTING vscous OILS FiledNov. l0, 1955 PIPEUNE n Y 2,876,081 Patented Mr. '3, 1959 2,87 6,081APPARATUS FOR TRANSPORTING VISCOUS OILS Shelby D. Lawson, Bartlesville,Okla;,.assignor to Phillips Petroleum Company, a corporation ofDelawareApplication November 10, 1955, Serial No. 546,211 1 Claim. (Cl. 23-288)This invention relates to a method of and apparatus for preparing oilsof high viscosity for transportation through a pipe line.

It is known that crude oils produced from several. fields are waxy andhave high pour points. For example, Roosevelt crude oil from UintahBasin has a pour point of approximately 100 F. Oils of this typeobviously cannot be transferred through pipe lines because they are tooviscous to flow at normal temperatures. Heretofore, oils of this typegenerally havebeen transported by tank cars or trucks. Such overlandtransportation is relatively expensive compared with pipe linetransportation and for this reason is not desirable. One method whichhas been proposed for transporting high viscous oils by pipeline is toheat the oil at intermediate locations along the pipe line to maintainthe temperature of the oil above its pour point. Heaters employed forthis purpose can be operated by withdrawing for fuel a portion of theoilbeing transmitted. However, this procedure may result in the loss of asmuchas 15 to 20 percent of the crude oil. Another method proposed toreduce the pour point of the oil employs thermal visbreaking. However,this procedure results in substantial quantities of gases beingproduced. Still another method which has been proposed involves dilutingthe oil with a natural gasoline. However, this procedure requires asupply of natural gasoline at the pumping station, which in many iieldsis not available.

In accordance with the present invention a system is provided to reducethe viscosity of crude oil suiciently to permit the oil to betransported through a pipe line. A portion of the crude oil to betransported is directed to the inlet of a catalytic cracking unit. Theproducts from the cracking unit are mixed with the remainder of thecrude oil to produce a blend having a pour point suiiiciently low topermit passage through a pipe line at ambient temperature conditions.The cracking can be accomplished by fluid catalyst cracking, moving bedcatalytic cracking, or xed bed catalytic cracking. In general, the fluidtechnique is preferred. Although it is realized that any crackingprocess employed on crude oil has a detrimental eiect on the straightrun distillates produced therefrom, the present day use of hydrogenationin refining substantially eliminates this undesired effect. By employingcatalytic cracking, a maximum amount of products in the gasoline rangeis produced with a minimum loss of product as gases. The produced gasescan be employed as fuel in the cracking unit.

Accordingly, it is an object of this invention to provide a -rnethod ofpreparing viscous oils for transportation through pipe lines.

Another object is to provide apparatus to treat viscous oils forsubsequent transportation through pipe lines.

Other objects, advantages and features of the inven tion should becomeapparent from the following detail description of a present preferredembodiment of the invention taken in conjunction with the accompanyingdrawing which is a schematic representationof apparatus employed tocarry out the method of this invention.v`

Referring now to the drawing in detail, there is shown an inlet conduit10 which delivers crude oil from apro-` ducing eld to a storage tank 11.Tank 11 is supplied with a heating coil 12 which'may be needed tomaintain the crude oil uid if it is stored for prolonged periods in cooltemperatures.V A portion of the oilremoved from tank 11 is directedthrough conduits 13, 14 and 15 to an accumulator 16. The remainder ofthe oil removed from tank 11 passes through conduit 13, a heat exchanger17 and a conduit 1S to the inlet of a lluid catalytic cracker reactor1,9. Regenerated cracking catalyst is directed from a regenerator 20through a conduit 21 to reactor inlet conduit 18. Coked catalyst fromreactor 19 is removed through a conduit 23. Conduit 23 communicates witha conduit 24 which in turn communicates withthe inlet of regenerator 20.Air is introduced through con-l duit 24 to burn the carbon deposits offthe catalyst in regenerator 20.

Steam or other stripping fluid is supplied to reactor 19 through aconduit 26 to remove cracked products whichmay be adsorbed on thecatalyst. The cracked productsV are removed from reactor 19 through aconduit 28 which passes through an air cooler 29 and heat exchanger 17to conduit 15. Gases in the top of accumulator 16 are withdrawn for useas fuel through a conduit 30. A pre'- determined pressure is maintainedin accumulator- 16 by a pressure regulating valve 31 in conduit 30.

The fluid in accumulator 16 thus comprises a blend of the original crudeoil and the products from reactor 19. Thisblended oil is directedthrough a conduit 3 2 to an outlet storage tank 33. The oil is removedas de@ sired fromtank'33 through a conduit 34 whichl communi'- cateswith a pipeline 35.

Flue gases from regenerator 20 are removed through an overhead line 37which has a pressure regulating valve 38 therein. The heat content ofthese gases can be utilized to generate steam to supply conduit 26 or toheat tank 11. Regenerator 20 may be supplied with a cooling coil 39which has water circulated therethrough to prevent excessive heat risesin the regenerator. The steam produced by water being heated in coil 39can also be employed to heat tank 11 or to supply stripping material toreactor 19.

It is desired that the regenerator be operated at a temperature in therange of 1040 to l090 F. At higher temperatures the catalyst tends tobe'deactivated, and at lower temperatures the regeneration takes placeat an excessively slow rate. It is desired that the reactor bemaintained at a temperature in a range from 890 to 930 F. At highertemperatures excessive quantities of gas and coke are produced, and atlower temperatures the cracking takes place too slowly. In general,there is about a 4 to 5% increase in liquid volume when crude is passedthrough the cracking unit. It is preferred that accumulator 16 bemaintained at a temperature of approximately F. and at a pressure ofapproximately 50 p. s. i. g. This condenses all but about 5% by liquidvolume of the cracked products. The ethane and lighter are removed asfuel gas. At lower pressures excessive amounts of gases are formed inthe accumulator. Higher pressures generally are not objectionable buttend to increase the cost of the equipment. The catalyst can be anyconventional cracking catalyst such as, for example, natural or claycatalysts comprising, in general, activated montf cracking unit dependsto a large extent on the pour pointof thecrude. oil being treated. Ifthe pour point increases, a greater portion of the oil must be crackedto maintain a pumpable blend. Also the ambient temperature of the pipeline influences the required viscosity of the blended tluid.I YIngeneral, the ramount of crude oil directed to the cracking unitvaries'from about 5 to 30 percent. Obviously,Y less crude is cracked inthe summer than inV the winter.

, As a Vspecific example of the operation of this invention, itisassumed that a crude oil having a pour point of 100 F. is to betransported in moderate weather wherein a mixture having a pour point of65 F., for example, can readily be passed through a pipeline. It is alsoassumed that crude is removed from tank 12 at a rate of 1000 barrels perhour. Fifteen percent of this crude, 150 barrels per hour, is directedto the cracking unit through conduit18. The remaining 850 barrels perhour is passed directly to accumulator 16. The charge to the crackingunit results in the production of approximately 156 barrels per hour,based on equivalent liquid. Ofthis, approximately 8 barrels per hour,based on equivalent liquid, is lost as fuel gas. This gas contains mostof the ethane and lighter. The remaining 148 barrels per hour (156-8) isblended vwith the original 850 barrels per hour in accumulator 16 togive a total blend of 998 barrelsper hour. This blend has a pour pointofr approximately 65 F.

, It should be apparent that moving bed and iixed bed catalytic crackingsystems can also be employed in carrying out the process of thisinvention. These processes are, of course, well known to those skilledin the art and for this reason are not described in detail herein.

From the foregoing description it should be evident that there isprovided in accordance with this invention an improved process to treatcrude oilsof high viscosity to render them capable of being transportedthrough a pipe line. The essence of this invention is the catalyticcracking of a portion of the crude and the blending of the any externaldiluent to reduce the viscosity of the oil to be transported.

While the invention has been described in conjunction with the presentpreferred embodiment it should be evident that it is not limitedthereto.

What is claimed is:

Apparatus for preparing a viscous oil for transporta tion through a pipeline comprising an inlet oil storage tank, a uid catalyst reactor, aheat exchanger, first conduit means to direct oil from said tank throughsaid heat exchanger to the inlet of said reactor, a uid catalystregenerator, conduit means to direct spent catalyst from said reactor tosaid regenerator, means to introduce air into said r'egenerator, conduitmeans to direct regenerated catalyst from saidV regenerator to saidreactor, an accumulator, conduit means to direct cracked products fromsaid reactor through said heat exchanger in indirect heat exchange withthe oil supplied to said reactor to said accumulator, conduit means todirect a predetermined amount of .oil from said tank to saidaccumulator, and means to supply the blended products in said'accumulator to a pipeline.

References Cited in the le of this patent UNITED STATES PATENTS OTHERREFERENCES Fuel Oil Manual, Schmidt, The Industrial Press, New York, N.Y., publishers, 1951, pages 13B-135.

